This invention relates to attachment of a strap or band to a watch case, and more particularly to an improved arrangement of lugs suitable for a resin or plastic watch case which gives the appearance of thin lugs and yet provides the required strength.
Watch case attachments are well known in metal cases in which a pair of opposed lugs or horns on either side of the watch case are provided with holes for receiving a retractable spring bar passing through a hole in the end of the strap or band. This is the normal type of attachment for a strap to a watch case which has been used for many years with metal watch cases. More recently, watch cases of resin or plastic material have been used in wristwatches. These materials do not have the strength of metal cases, and consequently conventional lugs exhibit breakage unless they are made very thick, which leads to an unsightly appearance. Particularly, in the case of a round quartz analog watch with a maximum viewing area, where the bezel around the lens is to appear as thin as possible, the lugs for attaching the strap should also have a thin appearance when viewed from the top of the watch.
One type of construction which has been used in a plastic watch case is the employment of multiple interleaved hinged elements which provide additional strength needed in a plastic case attachment. One example of such a construction is seen in U.S. Pat. No. 4,561,077 issued Dec. 24, 1985, which in its preferred form employs four lugs rather than two on either side of the watch case. A cover portion between lugs which is integral with the bezel serves partially to conceal the interleaved strap hinge elements.
Attachments have also been proposed in which a cross-member between lugs and metal cases provides a concealing ledge, as shown in U.S. Pat. No. 4,432,654 issued Feb. 21, 1984, or as shown in U.K. Patent Application GB 2087710A published June 3, 1982.
An improved thin lug construction for a resin case with the required strength would give more freedom to a watch designer to proportion the lugs with respect to the rest of the watch case from an esthetic standpoint rather than from the dictates of necessary physical strength.
Accordingly, one object of the present invention is to provide an improved resin watch case and lug construction for attachment to a conventional watchband.
Another object of the invention is to provide an improved resin watch case with the appearance of thin lugs with the necessary strength.